EGR - Exhaust Gas Reticulation - I think is reuses unburnt fuel, EPA regulation, keeps it legal emissions wise.
delcowizzid, Pacemaker are certainly excellent, many will say the best, a difference in performance of headers i doubt i will notice, a difference in price definately. THere are dynos floating around showing other brands better performance wise eg. Advance Headers (Press bent, Try-Y) but can they be taken as gospel, Who knows.......... In my choice i wanted the coating done as well, so i shopped around for the best price fitted as i cannot weld etc, and went with that. Especially when speaking to some reputable Exhaust specialist, my choice was limited to Genie and Pacemaker.